Cystitis treatment with high dose chondroitin sulfate

ABSTRACT

Interstitial cystitis and related GAG-deficient conditions of the bladder and urinary tract are treated by instillation of high dose chondroitin sulfate, such as 400 mg/20 mL. The higher dose of chondroitin is effective for the rapid reduction of symptoms, particularly in patients with severe and otherwise recalcitrant cystitis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 10/546,511, filedAug. 18, 2005, now U.S. Pat. No. 7,772,210, issued Aug. 10, 2010, whichapplication is a national phase entry under 35 U.S.C. §371 of PCTInternational Patent Application PCT/CA2004/000244, filed Feb. 18, 2004,published in English as PCT International Patent Publication WO2004/073584 A2 on Sep. 2, 2004, which application is a continuation inpart of U.S. Ser. No. 10/367,970, filed Feb. 19, 2003, now abandoned,the contents of the entirety of each of which are incorporated herein bythis reference.

FIELD OF THE INVENTION

The invention relates to therapeutic agents and methods useful in thetreatment of cystitis, including interstitial cystitis, and relatedbladder conditions.

BACKGROUND

Interstitial cystitis is a bladder condition associated with discomfortand pain elicited by urinary irritants, causing urgency for, andincreased frequency of, urination. Because its cause is poorlyunderstood, the development of useful treatments has followed approachesthat are largely empirical. These approaches have failed to yield morethan a few useful therapeutic agents and treatments. As described bySant and La Rock in Interstitial Cystitis, Vol. 21 (1), February 1994 atp. 73, current therapies include pharmacotherapy, with intravesical useof dimethyl sulfoxide being the only therapy approved by the FDA. Still,a variety of other agents are in use to treat symptoms of interstitialcystitis, either alone or in combination with DMSO. Such agents includesodium oxychlorosene (Clorpactin), heparin, hyaluronic acid, steroid,sodium bicarbonate, silver nitrate, sodium pentosanpolysulfate, cromolynsodium, lidocaine and doxorubicin. Many of these agents can be deliveredorally, but can be most effective at the GAG surface layer of theurethelium when delivered by instillation either as monotherapy,combination therapy or sequential therapy. These agents and therapiestarget the bladder mucosal lining, and provide symptomatic relief ofpain, frequency and urgency. Of these therapies, however, few offerrelief over sustained periods.

More recently, we have described the use of chondroitin sulfate as aninstilled preparation for the treatment of interstitial cystitis andrelated bladder conditions (see, U.S. Pat. No. 6,083,933 and CA 2269260assigned to Stellar International Inc.). As disclosed in these patents,preparations containing 80 mgs, and up to 200 mgs, of chondroitinsulfate as a 40 mL instillation provided relief from at least onesymptom including frequency, pain and urgency, in patients diagnosedwith cystitis. In addition, there is described a diagnostic methoduseful to identify responders to chondroitin sulfate therapy or therapywith other cystitis treatments. In this approach, patient candidatesfirst receive an instilled dose of an irritant such as potassiumchloride, and responders are then identified as those patientsexperiencing relief from the irritant-elicited symptoms uponinstillation of the chondroitin sulfate or other therapeutic. For use insuch therapy, Stellar International Inc., of London, Ontario, Canadamarkets the product Uracyst-S™, which is a treatment kit comprising avial containing 80 mgs of chondroitin sulfate in 40 mL aqueous vehicle(0.2%), and the product Uracyst-S™-Concentrate providing a vialcontaining 200 mgs of chondroitin in a 10 mL vehicle (2.0%). Results ofa study using Uracyst™-S are reported by Steinhoff et al in Can. J.Urol., 2002 Feb. 9(1):1454-58.

SUMMARY OF THE INVENTION

It has now been found that patients suffering from cystitis and relatedconditions of the bladder and urinary tract respond more rapidly totreatment with chondroitin sulfate when the instilled dose ofchondroitin sulfate is increased above 200 mg. It had been assumed thata dose approaching 200 mg was sufficient to saturate the bladder liningand hence deposit, or adsorb, sufficient chondroitin sulfate to protectall available sites of bladder lining erosion. However, it has nowsurprisingly been found that a more rapid relief from cystitis symptomscan be realized when the instilled dose of chondroitin sulfate isincreased, beyond 200 mgs. In addition, it has been found thatadministration of higher dose chondroitin sulfate provides relief inpatients in whom the cystitis is so severe as to be virtually refractoryto other conventional forms of cystitis therapy.

Thus, in accordance with one aspect of the invention, there is provideda method for treating a patient afflicted with cystitis or a relatedcondition of the bladder or urinary tract, the method comprising thestep of delivering to the patient by instillation a pharmaceuticalcomposition comprising chondroitin sulfate in a unit dose of at least250 mgs, preferably at least 300 mgs, more preferably at least 350 mgsand most preferably at least 400 mgs. Similarly, the invention providesfor the use of chondroitin sulfate in the preparation of a medicamentcomprising at least 250 mgs of chondroitin sulfate for the treatment ofcystitis and related conditions of the bladder or urinary tract.

In other aspects of the invention, there is provided a pharmaceuticalcomposition adapted for delivery to a patient by instillation, thecomposition comprising chondroitin sulfate at a unit dose of at least250 mgs, and an aqueous vehicle therefor. In embodiments of theinvention, compositions effective to treat cystitis include sterile,aqueous compositions comprising:

(1) a unit dose of highly purified grade chondroitin sulfate of at least250 mgs, e.g., in the range from 250 mgs to saturation, and

(2) a pharmaceutically acceptable aqueous carrier, in a volume that ispatient-tolerated and sufficient for exposing the bladder surface areato be treated.

In a particular embodiment of the invention, there is provided apharmaceutical composition adapted for instillation, the compositioncomprising chondroitin sulfate in a unit dose of from 250 to 1200 mgs,and from 10 to 100 mL of an aqueous vehicle. In a more specificembodiment, the composition comprises 400 mgs of chondroitin sulfate in20 mL of an aqueous vehicle, preferably phosphate-buffered saline. In avery specific embodiment, there is provided a sterile chondroitinsulfate solution adapted for instillation, the solution consistingessentially of, and preferably consisting only of, 400 mgs ofchondroitin sulfate and 20 mL of an aqueous buffer, preferablyphosphate-buffered saline.

BRIEF REFERENCE TO THE DRAWING

FIG. 1 compares, using the Oleary Sant index, results obtained incystitis patients receiving high dose chondroitin sulfate, with resultsachieved in patients receiving an 80 mg dose of chondroitin sulfate.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS

The compositions and methods of the invention are useful in thetreatment and assessment of various forms of cystitis as they occurparticularly in the bladder, but also as they occur in the urinary tractincluding the urethra and those other mucosal surfaces that are exposedto treatment by the vesicular instillation route of administration. Bythis route, a sterile catheter is placed into the bladder through theurethra, and the treatment solution fed through the catheter. Thesolution is then held in the bladder for at least 30 minutes or longerbefore voiding. The forms of cystitis that can be treated includeparticularly interstitial cystitis and those other forms of cystitis andrelated bladder conditions that respond to an enhancement of mucosalintegrity and barrier function that is believed to result when thepresent chondroitin sulfate treatment is used. These includeradiation-induced cystitis, chemical-induced cystitis, e.g., resultingfrom chemotherapy and hemorrhagic cystitis, as well as, more generally,GAG-deficient forms of cystitis and GAG-deficiency resulting fromchronic urinary tract infection.

Cystitis-related conditions are revealed using an established potassiumtest, in which a 3.0% KCl solution is instilled into the bladder of thepatient candidate. A response to the potassium solution with symptomscharacteristic of cystitis indicates GAG deficiency in the bladderlining, suggesting that the patient has either cystitis or a conditionrelated thereto by GAG-deficiency, and identifies the patient as acandidate for chondroitin sulfate therapy.

For use in treating interstitial cystitis and these related conditions,the invention exploits chondroitin sulfate which is an acidicmucopolysaccharide and is one of the glycosaminoglycans (GAGs). Itsrepeating disaccharide unit is made of glucuronic acid and galactosaminewith one sulfate group in a B (1-3′) linkage, i.e. N-acetylgalactosamine sulfate. This disaccharide unit is polymerized in B (1-4′)linkage.

Chondroitin sulfate (CS) is available in a number of mono-sulfatedforms, varying according to specific chemical composition usually asrelated to extraction source, chain length usually as related toprocessing techniques, degree of sulfation, etc. For use in theinvention, the CS is desirably in pyrogen free form and is highlypurified, thus yielding an “injectable grade” of material having thequalities required for human use by the various regulating agencies.Such material is available from a variety of commercial sources, and thepresent literature is replete with descriptions of methods suitable forproducing such material. In embodiments of the invention, the CS iswithin the molecular size range of from about 1,000 Daltons to about75,000 Daltons, for example from about 10,000 Daltons to about 40,000Daltons. A suitable natural source for CS within this size range is softconnective tissue, such as cartilage. In a specific embodiment, the CSstarting material is obtained from either porcine or bovine cartilageand subsequently refined by established methods to yield the desiredinjectable grade and molecular size fractionated CS. Alternatively, itwill be appreciated that the CS can be obtained from other sources,including synthetic routes, or can be blended to combine synthetic andnatural CS forms into the desired composition. Desirably, but notessentially, the CS comprises the A-form and C-form of CS, in a blend ofform 3:1 to 1:3 on a molar basis, e.g., about 1:1.

It will be understood that the CS typically is in salt form, and inaccordance with embodiments of the invention, is in the sodium saltform.

For use, the CS is formulated as a sterile, aqueous solution. Theformulation is desirably adapted for single dose administration,although it will be appreciated that a multi-dose formulation may beutilized to treat a number of patients.

In accordance with the invention, the unit dose of CS administered tothe patient is at least 250 mgs. More desirably, the unit dose of CS isat least 300 mgs. Preferably, the unit dose is at least 350 mgs. Morepreferably, the unit dose is at least 400 mgs. The upper end of theacceptable unit dose is capped, in theory, only by the solubility of thegiven type of CS in the chosen aqueous vehicle, and by the volume ofthat vehicle used in therapy. At room temperature and in sterile,distilled water, the solubility of CS approaches 50%. Thus, the upperlimit of the CS unit dose can be 500 mgs/mL of vehicle. In accordancewith the invention, the unit dose of CS is desirably formulated in asolution volume that is sufficient to expose the bladder surface to betreated, and is at least tolerable and more desirably comfortable forthe patient. The upper limit for such volumes lies below the volumecausing hydrodistention, which is about 250 mL in some patients. Foradult patients, solution volumes are suitably from about 5 mL or 10 mLup to about 100 mL, e.g. up to about 75 mL, and preferably up to about50 mL. In a specific embodiment of the invention, a solution volume ofabout 40 mL is utilized. Accordingly, the upper limit of the unit doseof CS administrable to the patient at this volume can approach 20,000mgs.

In embodiments of the invention, the unit dose of CS administered to thepatient lies suitably within the range from 250-1,200 mgs, desirablywithin the range from 300-800 mgs, preferably in the range from 350-600mgs, and more preferably in the range from 375-500 mgs. In a specificembodiment, the CS is formulated in a unit dose of 400 mgs.

As vehicle for such solutions, there may be employed sterile water,saline or buffered saline. The saline vehicle is particularly useful,and in embodiments of the invention, the vehicle is 0.9% saline.Alternatively, phosphate-buffered saline vehicles may be used. In aspecific embodiment, the aqueous vehicle is simply sterile water forinjection.

The concentration of CS within the solution will of course vary inaccordance with the amount of CS formulated and the solution volumeemployed. CS is relatively soluble in aqueous vehicles, and a wide rangeof concentrations may therefore be formulated. In embodiments of theinvention, the CS concentration lies within the range from 0.1 mg/mL to100 mg/mL, preferably 1.0 mg/mL to 50 mg/mL. In a specific embodiment ofthe invention, the formulation has a CS concentration of about 15-25mg/mL, e.g., 20 mg/mL. In a particular specific embodiment of theinvention, the formulation achieves this concentration by providing aformulation containing 400 mgs of CS in a 20 mL volume ofphosphate-buffered saline.

In a specific embodiment of the invention, the sterile chondroin sulfatesolution consists of 400 mgs chondroitin sulfate, and 20 mL of aqueousvehicle, such as sterile water, saline or phosphate-buffered saline.

Formulation of the CS will of course be performed in a mannerestablished in the pharmaceutical art. Unit or single doses can beproduced simply by metering the unit dose of CS, say 400 mgs, into avial which then receives 20 mL of vehicle or diluent, under asepticfilling conditions. Alternatively, such a formulation can be prepared bycombining commercially available formulations, such as theUracyst-S-Concentrate, e.g., by combining two 200 mg/10 mL solutions.

In use, the CS composition is administered by instillation or likemethod that directs the composition to the luminal (mucosal) surface ofthe affected bladder or associated surface of a patient having thesymptoms of cystitis and particularly GAG-deficient cystitis includingchemical- and radiation-induced cystitis, hemorrhagic cystitis and, inaccordance with a preferred embodiment of the invention, interstitialcystitis. In addition to IC patients, such treatment can be useful, asnoted, for “related bladder conditions”, i.e., for those patients havingan erosion of either the bladder lining or the lining of the urethra orureters which is sufficiently severe to cause pain or discomfort whenchemical irritants are present in the urine. Such related conditionsinclude urinary tract GAG-deficiency resulting from chronic urinarytract infection. With each treatment, the composition is instilled, forinstance as a 20 mg/mL dose of CS in a buffer volume of 20 mL, after anyresidual urine has been removed. The patient then retains the solutionfor a period desirably of not less than 30 minutes. In a typicaltreatment regimen, weekly or biweekly treatments are performed for about6 weeks, and then monthly treatments are performed thereafter untilsymptoms are relieved. Some patients may benefit from up to 6 weeklyinstillations, then instillations once monthly or bi-monthly thereafterdepending on their symptomatic response. Maintenance dosing can beperformed using doses of CS that are reduced, e.g., to 200 mgs, ifpatient symptoms so indicate.

As noted in the examples, patients treated in the manner just describedhave responded well, by indicating that symptoms of pain, urgency and/orfrequency have subsided. The present success with “high dose”chondroitin sulfate is both a surprising and significant result, given,on the one hand, that chondroitin sulfate is both a commerciallyavailable and relatively inexpensive agent and, on the other hand, thatso few agents tested for IC are found to provide actual benefit to thepatient. Patients treated with the high dose chondroitin sulfateresponded very rapidly to treatment. Moreover, the success seen in theexamples herein provided has been achieved in patients having severecystitis symptoms who were otherwise refractory to treatment with otheravailable therapies.

It will be appreciated that the present high dose CS therapy can beutilized either as a monotherapy or in combination with other availablecystitis treatments. Such known cystitis therapies include thosedelivered by instillation, such as DMSO, heparin, pentosanpolysulfateand hyaluronic acid. As noted hereinabove, such agents should beadministered in a volume sufficient to bathe the bladder lining with anamount of the agent determined to be suitable for investigating atherapeutic effect.

For use in the therapeutic method of the invention, there is furtherprovided by the invention a kit comprising, in combination,

(1) a first sterile solution comprising chondroitin sulfate at a unitdose of at least 250 mgs and an aqueous vehicle; and

(2) printed instructions teaching the use thereof in accordance with thepresent treatment method.

Such a kit may take the form of a box or other package in which thesterile solution is provided as a ready-to-use solution, having theconcentration and unit dose described hereinabove. The printedinstructions will convey to the end-user the methodology of theinvention. That methodology is exemplified below.

EXAMPLES

The following describes the treatment of interstitial cystitis patientsin a clinical setting.

For use in treatment, chondroitin sulfate, as the sodium salt, waspurchased as non-pyrogenic and highly purified grade. The CS wasobtained from bovine cartilage to control its purity and composition ofchondroitin sulfate in terms of its isomers A/C (60:40) andcarboxyl/O-sulfate ratio (about 0.95), with other specifications beingthe following:

-   -   Appearance: white to slightly off-white highly hygroscopic solid        powder    -   Purity (anhydrous basis): >98.0%    -   pH in 1% water: 5.5-7.5    -   Specific rotation (4% water): −20 to −30 degrees    -   Nitrogen (anhydrous basis): 2.5-3.5%    -   Sulfur (anhydrous basis): 5.0-7.0%    -   Sulfate ash (anhydrous basis): 21-29%    -   Heavy metals: <20 ppm    -   Chloride: <0.1%    -   Proteins (anhydrous basis): <1.0%    -   Pyrogen: pyrogen free    -   Average Molecular Weight: 10,000-40,000 Daltons \

This CS is formulated as a 20.0 mg/mL solution, by blending, thefollowing ingredients:

Formula Quantity Ingredient (per mL) Na Chondroitin Sulfate (asanhydrous) 20.0 mg Sod. Chloride, USP  8.5 mg Dibasic Sodium Phosphate7H2O, USP 0.42 mg Monobasic Sodium Phosphate 2H2O, USP 0.04 mg SterileWater for Injection., USP OR to Volume Sterile Water for Irrigation USPQS

For compounding, about 20 mL of water for injection, USP, is collected,and the required amount (20 times the amounts noted above per mL offormula to make a 2% solution) of Sodium Chloride is added and mixeduntil completely dissolved (a minimum of 15 minutes). The requiredamount of monobasic and dibasic Sodium Phosphate is then added and mixeduntil completely dissolved (a minimum of 15 minutes). Then, the requiredamount of Sodium Chondroitin Sulfate, is added and mixed untilcompletely dissolved (a minimum of 4 hours for hydration). If necessarythe pH is adjusted to 7.2 0.1 with 1N Sodium Hydroxide in WFI, USP or 1N Phosphoric Acid in WFI, USP. Then, add sufficient quantity to finalvolume with sterile water for injection, USP and mix thoroughly. It willbe appreciated that this method is also suitable for producing differentunit doses of CS, simply by altering the volume of buffer and/or byaltering the amount of CS and other noted ingredients. Thus, by thismethodology, there are provided such CS formulations as 10-40 mL, e.g.,20 mL, formulations containing 250, 300, 350, 400, 600, 800, 1,000 and1,200 mgs of CS.

The formulation can further comprise a preservative. In a specificembodiment, the preservative is benzyl alcohol or parabens, e.g.,methylparaben, propylparaben and butylparaben and mixtures. Forinstance, the preservative can be 1.5% w/v benzyl alcohol. In apreferred embodiment, the formulation is adapted as a unit dose, and thepreservative is accordingly not essential. Thus, in a specificembodiment, the formulation is essentially free from preservative, andother additives, and consists of aqueous vehicle, e.g. 20 mL, and thechondroitin sulfate, e.g., 400 mgs.

The compounded solution (2% or otherwise) is then sterile filled as10-40 mL, e.g., 20 mL, aliquots into 50 mL, molded Flint I type vialspreviously sterilized at 250° C. for 180 minutes, and stoppered using100% synthetic rubber stoppers of the 20 mm type. The vials are thenlabeled as sterile sodium chondroitin sulfate solution. Hereinafter, the400 mg/20 mL formulations, 2.0%, are referred to as “Uracyst-S-400”formulations.

In the alternative, patients received two doses of Uracyst-S-Concentrate(200 mgs/10 mL, purchased from Stellar Healthcare of London, Ontario,Canada) per instillation, to deliver 400 mgs of CS in 20 mL of thebuffer.

The CS so formulated (400 mg/20 mL [2.0% w/v], Uracyst-S-400) wasassessed, in a pilot study with six patients diagnosed with interstitialcystitis. All patients had positive potassium tests, negativecystoscopies and symptoms of daytime frequency of +8 and/or bladderpain. All patients completed an Oleary Sant questionnaire once a week.The three patients receiving twice weekly treatment completed the OlearySant once a week also. The potassium test was performed using theproduct “Solution K” sold by Stellar Healthcare in London, Ontario,Canada, i.e., by instilling a 3.0% KCl solution in the manner instructedby that supplier.

Patient #1 was referred from another urologist seeking a second opinionregarding a cystectomy. She complained of unremitting and severe bladderpain. She had not found success with any treatment. She received sixweekly treatments of intravesical Uracyst-S-400. There was noimprovement in her symptom/problem score, and she was referred back tothe urologist for cystectomy.

Patient #2 presented with long standing interstitial cystitis (IC) andhas had some success with previous treatment. She entered the pilotstudy due to a prolonged and painful flare-up of her IC. She receivedintravesical instillations of Uracyst-S-400 on Monday and Thursday forsix consecutive weeks. Her symptom and problem score improved each week.She was pain free at week 6.

Patient #3 also presented with long standing IC. She complained offrequent painful flare-ups that include severe frequency and nocturia.The patient was also diagnosed with irritable bowel syndrome (IBS). Shewas treated with Uracyst-S-400 twice weekly (Mondays and Thursdays) forseven weeks. Although two dosing intervals were missed, the patient'sproblem and symptom scores each dropped five points by the end of thetherapy. The patient continues on Uracyst-S-200 mg therapy q2 weeks andwill soon be placed on once monthly instillations at this dose. Hersymptoms continue to improve.

Patient #4 was referred for flare-up of IC. She had been on oraltreatment for 10 years and experienced frequent flare-ups. She wastreated once weekly with Uracyst-S-400 for six weeks. Each of herproblem and pain scores decreased/improved by 10 points. The patientcontinues with monthly instillations of Uracyst-S-200.

Patient #5 was referred for bladder pain and frequency, and presentsalso with fibromyalgia and osteoarthritis and is on medication for theseconditions. She was treated with weekly instillations of Uracyst-S 400for six consecutive weeks. The symptom score improved by 5 points andthe problem score by one point. The treatment improved her bladder painbut did not improve her frequency, so the problem score does not reflectthat improvement.

Patient #6 has long standing IC, fibromyalgia, emotional stresses,pelvic pain which may or may not be upregulation from her IC. She is onmany medications including morphine for pain. She was initially startedon weekly instillations and then switched to twice weekly after thefirst week. She received Uracyst-S 400 twice weekly for six weeks for atotal treatment time of 7 weeks. Although symptom and problem scoreswere somewhat equivocal owing largely to stresses raised by her otherconditions, some improvement was noted. Treatment continues every twoweeks with Uracyst-S 200, and will soon be reduced to once monthlydosing.

Thus, six patients with known Interstitial Cystitis were instilledintravesically with Uracyst-S 400 (400 mg in 20 mL phosphate buffersaline) either weekly or twice weekly for 6 weeks. Four of the patientswere refractory to other forms of treatment, one patient was in aflare-up while on Elmiron®, and one was new to treatment. Three of thefour refractory patients were instilled twice weekly with URACYST-S 400mg. There were no side affects that could be associated with theinstillation of the solution. One patient complained of feeling worseafter the first instillation but did not want to stop thetreatment-after switching to a self-lubricating catheter; there were nofurther complaints of feeling worse. One patient stated she had a 10minute total body flush one hour post instillation on the first twoinstillations; this did not occur on subsequent instillations. Thereappears to be a shorter time to improvement with the 400 mg Uracyst-Shas thus demonstrated that it provides faster relief of problems andsymptoms of IC patients. Three of the refractory patients had mild tosignificant improvement. The two non refractory patients showedimprovement in the six weeks of instillation.

The improvements in voiding and pain seen in this patient population aregraphed in FIG. 1, according to scores recorded using the Oleary Santscoring system established for interstitial cystitis. It will be noted,as a trend, that this patient population reported overall significantimprovement in symptoms over the noted course of therapy (“400 Symptom,400 Problem”). For comparison, FIG. 1 also shows the improvement insymptom scores in a patient population, albeit a different interstitialcystitis patient population, treated with chondroitin sulphateformulated at 80 mgs/40 mL (“80 Symptom, 80 Problem”). As shown, the 400mg dosing therapy provided significant improvement in patients withsymptoms and problems more severe than those treated with at the 80 mgdose. The 400 mg population, for instance, scored above 12 in bothcategories assessed, compared with a score of 12 or less in the 80 mgpopulation. Moreover, the rate at which those symptoms were improvedusing the 400 mg dose was far more rapid than in patients receiving the80 mg dose.

It will thus be appreciated that high dose chondroitin sulfate providesa therapy useful in the treatment of patients suffering from cystitis,and is particularly useful for the treatment of patients presenting withsevere or long-term interstitial cystitis and related forms ofGAG-deficient cystitis.

1. A method of treating cystitis in a subject in need thereof, themethod comprising: treating the subject with a pharmaceuticalcomposition comprising: a unit dose of chondroitin sulfate in an amountof at least 350 mg, and an aqueous vehicle in a volume of from 10 mL to100 mL, wherein the pharmaceutical composition is adapted forinstillation to the bladder of the subject, so as to treat the cystitisin the subject.
 2. The method according to claim 1, wherein thechondroitin sulfate is present in an amount of 400 mg.
 3. The methodaccording to claim 1, wherein the aqueous vehicle is present in anamount of 20 mL.
 4. The method according to claim 1, wherein the aqueousvehicle is phosphate-buffered saline.
 5. The method according to claim1, wherein the cystitis is interstitial cystitis.
 6. The methodaccording to claim 1, wherein treating cystitis with the pharmaceuticalcomposition comprises: providing a subject afflicted with cystitis or arelated condition in which one or more cystitis symptoms are elicited inthe subject afflicted upon instillation of a potassium chloridesolution; and instilling the pharmaceutical composition into the bladderor urinary tract of the subject.
 7. The method according to claim 6,wherein the instilling is performed at least once weekly for a period ofat least 6 weeks.
 8. The method according to claim 6, wherein theinstilling is performed at least twice weekly for a period of at least 6weeks.
 9. The method according to claim 1, wherein the unit dose ofchondroitin sulfate is at most equivalent to the solubility ofchondroitin sulfate is said vehicle.
 10. The method according to claim1, wherein the unit dose of chondroitin sulfate is less than or equal to1200 mg.
 11. The method according to claim 1, wherein the unit dose ofchondroitin sulfate is less than or equal to 800 mg.